The present invention relates to magnetic tape recording devices, or the like, which are capable of recording or registering random, transient signals, or the like, the starting time of which is unknown. The apparatus of the present invention is especially useful in disturbance recording in that a magnetic tape is provided which thereafter may be electronically analyzed.
The apparatus of the present invention is adapted to record signals representing a phenomenon to be studied, including those phenomenons whose origins are physical, mechanical, chemical, electrical, electronic, or the like. Often the phenomenon of interest occurs as abnormalties in the observation of another phenomenon. The ability to observe, locate, and analyze such abnormal phenomenon permits one to study their origin, and evolution and thereby provide for safer and more reliable systems.
Present registering devices use the following basic elements:
A temporary data carrier, a final data carrier, and a device to cause the transfer of the data from the temporary carrier to the final carrier. The transfer device may operate from an order which may be included in the data on the temporary carrier or from auxiliary data.
Existing disturbance recording techniques may take the following form: oscillographs, numerical storage recorders, or magnetic tape recorders. While these devices have certain advantages they also have disadvantages with respect to disturbance recording techniques. Oscillographs have no electronic output for transferring the information, the narrowness of the screen limits the duration of the phenomenon to be observed, there is a preset lag valve, the indicated threshold cannot be accurately determined, the reading precision is low. In addition, the surveilance or watching of the disturbance phenomenon is halted during the storage of interesting data. With respect to numerical storage registers, the amount of data to be stored is limited by the storage registers. Also, the content of the storage registers is not readily transferable due to the fact that the device must remain current carrying. The pass band is inversely proportional to the delay and interdependent on the number of channels. In addition, surveilance is halted during the storage of desired data. With respect to magnetic tape recorders, they usually employ a tape formed in a loop. The frequent passage of the tape causes wear on the loop and the magnetic head. As in the case of the oscillographs and the numerical storage recorders, the surveilance of the phenomenon is often stopped during the loop reading. In addition, magnetic tape recorders of this type are usually expensive.
The present invention overcomes the drawbacks which have characterized prior art devices by providing an apparatus which records disturbances or abnormalties as well as other interesting data in a continuous manner in which the surveilance is not interrupted; advantageously groups the recording of the disturbances on a magnetic tape or other carrier thereby reducing the unused lengths of tape and provides a device in which the observation or surveilance mode is essentially automatic.
The present invention provides an apparatus which achieves these goals and which is capable of recording a phenomenon and thereafter storing it.
A principal characteristic of the present invention is the driving of a magnetic tape in a forward and reverse direction while watching for a signal to be recorded. As soon as such a signal occurs, the forward and reverse motion of the tape is halted and the tape is run in a direction which enables it to be wound on the reception reel with the recorded message. As soon as the information to be recorded is halted, the recorded information is taken out of the surveilance loop and wound onto the takeup reel, while a second reel, called the supply reel, provides an unrecorded length of magnetic tape. This tape is then driven in a forward and reverse motion during a surveilance cycle. Should another signal of interest occur, the recording heads, according to loop position, record this second signal by stopping the surveilance cycle and operating in a recording mode.
The loop forming system includes multi-roller systems having stationary rollers and movable rollers. The movable rollers entrained the tape and may be moved to increase or decrease the length of the loop.